The present invention relates to an improved assembly including means for optical communication between separate containers, and more particularly to an improved assembly for optical communication between low voltage electronic components housed in one container and high-voltage electronic components housed in another container that is insulatively attached to the one container.
In typical microwave communication systems, a traveling wave tube is pulsed at a predetermined frequency by a high-voltage pulsing device that is located within a sealed pressurized housing or container. The high-voltage pulsing device is controlled exterior of its sealed housing by a low-voltage pulsing device positioned within another housing or container. In the past, the two pulsing devices were inductively coupled by a transformer, which, necessarily was relatively large, and required precise construction and insulation. These inductively coupled pulses were subject to operational as well as structural shortcomings. For example, as the frequency of the pulses decreased or increased, the wave shape of such pulses changed. In order to eliminate the inductive coupling of the high-voltage and low-voltage pulses, an assembly was devised that optically coupled separate high voltage and low voltage pulses. With this arrangement, a low voltage pulse forming network switched a light-emitting diode (LED) "on" and "off" at a predetermined rate in accordance with the desired pulse width and frequency. The light from this LED was transmitted via a fiber optic guide into a high-voltage housing for reception by a photodiode. The photodiode, which was mounted in a housing that was in turn located in a pressurized housing operated the high voltage pulse forming network which pulses the traveling wave tube. Although optical coupling with fiber optics overcame the problems associated with a transformer coupling, and was satisfactory for the purpose intended, other problems became manifest. For example, such an assembly required sufficient space to route the flexible fiber optic light guide within the high-voltage pressurized assembly so as to have sufficient clearance to prevent high-voltgage breakdown. The flexible fiber optic light guides, of course, were required also to be sealed where they entered the pressurized container to prevent dielectric leakage from the high-voltage assembly. In addition to the more complicated construction of such prior art assemblies, during assembly and maintenance, the flexible optical fibers would occasionally break resulting in a reduced light reception, and at times dielectric fluid escaped from the pressurized housing through the interstices of the light fibers.
Thus, it is desirable to provide an improved assembly where low-voltage and high-voltage components, which are housed in separate containers, are optically coupled such that the problems associated with flexible optical fibers are overcome, and at the same time, permits relative simplicity of construction and maintenance.